I designed this solder fume extractor to replace another more basic one I 3D printed that I wasn't happy with for several reasons. No real filtration, depended on horizontal air flow, didn't stay positioned very well, and it broke at it's hinge joint more than once.

This one is designed to take a 125x125x28mm HEPA filter and can also incorporate a 125,125,10mm activated charcoal sponge filter (or other) to serve as a pre-filter to catch larger dust particles, pet hair, lint etc before they clog the HEPA filter. This also uses a stiff, flexible hose to place the inlet above your work. The optional outlet duct helps with directing the airflow out in a more uniform direction and doubles as a blade guard.

This is a large print and you need a 290mm or larger print bed.

I also included the design I used with power switch and cable strain relief openings and the box with no additional opening so you can modify it to your needs. Since I recycled those components I can't tell you where to get the exact same ones I used.

Additional supplies need:

6 x screws (Preferably coarse thread for plastics roughly 8mm x 3mm in size)
1 x Flexform 2.25" (58mm) hose kit https://www.amazon.com/POWERTEC-70208-Dust-Collection-Flexible/dp/B073ZX47FZ (or similar)
1 x 120mm high CFM fan https://www.amazon.com/AC-Infinity-Cooling-Ventilation-Projects/dp/B009OWRMZ6 (or similar)
1 x 125mm HEPA filter https://www.amazon.com/gp/product/B07C9QZNFK (or similar)

(Optional)
1 x 125mm activated charcoal sponge filter https://www.amazon.com/gp/product/B07D5SBPN8 (or similar)
1 x power switch
1 x power cord strain relief

The links above are to suggested products to use to help you identify what they are, but those are by no means the best or only products to use. I am using that same 120mm AC fan and I can say at 110CFM that is just enough air flow to work. It works fairly well if you place the duct with the rectangular inlet on it as close to your work as you can. I have also tested it positioned to the side and that only works if you are very close to the inlet (50cm to 100cm max). The outlet duct does seem to help with mine too. I think its helping to direct the exhaust and prevents it from creating a slight draft around the work area, but I think I get more distance from the inlet when it is installed.

Other possibilities are to hook the box up to a larger fan via a duct or otherwise externally mounted and just use this housing as the filter box.

(Updated Sept. 2021)
I added an optional inlet velocity stack. It will fit inside if your fan is 1.5" (40mm) or thinner. My hope was to get the air into the fan more efficiently. It only fits in one way with the thinnest side toward the top of the box (see images). Also depending on how you are mounting this on the fan it may be difficult to attach since access to 2 of the mounting holes will be blocked. If you are using 9/32 nuts on long bolts like I am then you can print the nut block (2x) and put the nut inside it then glue it to the flange (see images) on the top two corners.

The outlet helps direct the air out in one direction. I found that without it the air comes out in a very wide cone (nearly sideways) and blows air in directions I don't want. It also doubles as a grill to keep your fingers out of the fan.

Inlet and outlet are optional. Use them if you want.